In many electronic applications, one or more microphones may be needed. For example, in communications devices, a microphone is needed to convert an audio signal (e.g., voice) to an electrical signal for transmission to a receiver. One or more additional microphones may be included in the communications device to provide noise cancellation of ambient noise.
Micro-electromechanical systems (MEMS) based microphones have received interest as candidates for various applications. One type of MEMS microphone is a capacitive-based microphone. A capacitive microphone normally includes a fixed plate and a floating plate. Steps must be taken to avoid contact between the plates. This may be accomplished using stand-offs, which maintain a minimum spacing between the plates. In order to provide noise cancellation using capacitive microphones, a rather complex plate structure must be fabricated. As will be appreciated, there are manufacturing complexities and reliability concerns associated with known capacitive microphone structures.
What is needed, therefore, is a microphone structure and an electronic device that address at least the shortcomings described above.